Correlates of dietary behavior in adults: an umbrella review

In order to inform interventions to promote healthy eating, insights in the potential determinants of dietary behaviour is important. Interventions should target such determinants to initiate dietary behaviour change. Multiple studies have been conducted on potential determinants of dietary behavior in adults, but a clear overview is currently lacking. In an open access paper just published in the journal Nutrition Reviews, with Dr. Esther Sleddens as first author, we describe a so-called umbrella review -or a review-of-reviews-  to summarize and synthesize the scientific evidence on correlates and determinants of dietary behavior in adults. We included reviews published between January 1990 and May 2014 and 14 reviews were considered eligible. We evaluated the strength of the evidence, and the methodological quality.
Social-cognitive determinants and environmental determinants (mainly the social-cultural environment) were included most often in the available reviews. Sedentary behavior and habit strength were consistently identified as important correlates of dietary behavior. Other correlates and potential determinants of dietary behavior, such as motivational regulation, shift work, and the political environment, have been studied in relatively few studies, but results were rather consistent. Because of the generally weak research design of the studies covered in the available reviews, the evidence for true determinants is suggestive, at best.

Breaking up sitting time among schoolchildren

Children sit too much and too long. Especially prolonged sitting may be detrimental to health, and breaking up sitting time -i.e. introducing short interruptions of sitting-, may be health promoting. There are currently no studies available reporting intervention effects on breaking up children’s sedentary time. In a study just published in Paediatric Exercise Science, with Dr. Maite Verloigne as first author, we examined the 'UP4FUN' intervention's effect on objectively measured number of breaks in sedentary time, number of sedentary bouts (≥ 10 mins) and total and average amount of time spent in those sedentary bouts among 10- to 12-year-old Belgian children. The total sample included 354 children (mean age: 10.9 ± 0.7years; 59% girls) with valid ActiGraph accelerometer data at pre- and posttest.
Only few and small intervention effects were found, namely on total time spent in sedentary bouts immediately after school hours and on average time spent in sedentary bouts before school hours ( and immediately after school hours in favor of children from intervention schools. Unexpectedly, girls from intervention schools decreased the number of breaks during school hours and increased the number of sedentary bouts on a weekend day, whereas girls in control schools showed an increase in number of breaks and a decrease in number of bouts. In conclusion, UP4FUN did not have a consistent or substantial effect on breaking up children’s sedentary time and these data suggest that more intensive and longer lasting interventions are needed.

Exercise and health‐related quality of life in older long‐term prostate cancer survivors

In a study just published in the journal Cancer -with Dr. Laurien Buffart as first author-, we examined the effects of 12 months of exercise on health-related quality of life (HRQoL) in older long-term survivors of prostate cancer. We also studied for whom this intervention was effective and what possible working mechanisms of the intervention were, i.e. we studied moderators (for whom?) and mediators (how?) of the intervention effects.
In total, 100 men with a mean age of 71.7 years participated in and RCT, and were randomly assigned to 6 months of supervised aerobic and resistance exercise followed by 6 months of a home-based exercise maintenance program (EX group) or printed education material regarding physical activity for 12 months (PA group).
The results show that aerobic and resistance exercise appear to have beneficial effects on HRQoL among older, long-term survivors of prostate cancer. These effects were larger among patients who were married, who started exercising sooner rather than later after diagnosis, and who previously used bisphosphonates. Improvements in lower body functional performance as a result of the exercise intervention mediated the effects on HRQoL.

Successful behavior change in obesity interventions in adults

Overweight and obesity are among the main determinants of avoidable burden of disease worldwide. many interventions have been developed, tested and implemented to treat obesity. Many of such interventions aim at lifestyle changes -i.e. better nutrition, more physical activity to help people lose weight and avoid further weight gain. However, relapse is high in lifestyle obesity interventions involving behavior and weight change. Identifying mediators of successful outcomes in these interventions is critical to improve effectiveness and to guide approaches to obesity treatment, including resource allocation. In an article that just appeared in the journal BMC Medicine -with Prof. Pedro Teixeira as first author, and as part of the larger European Commission-funded Spotlight project-, we reviewed the most consistent self-regulation mediators of medium- and long-term weight control, physical activity, and dietary intake in clinical and community behavior change interventions targeting overweight/obese adults. Using a systematic review methodology we reviewed thirty-five studies testing 42 possible mediators of intervention effect. The results indicate that important prerequisites for medium-/long-term weight control were higher levels of autonomous motivation, self-efficacy/barriers, self-regulation skills (such as self-monitoring), flexible eating restraint, and positive body image. For physical activity, significant mediators were high autonomous motivation, self-efficacy, and use of self-regulation skills. For dietary intake, the evidence was much less clear, and no consistent mediators were identified. We conclude that despite limited evidence, higher autonomous motivation, self-efficacy, and self-regulation skills emerged as the best predictors of beneficial weight and physical activity outcomes; for weight control, positive body image and flexible eating restraint may additionally improve outcomes. These variables represent possible targets for future lifestyle interventions in overweight/obese populations.

An intervention to break up sitting time among schoolchildren was not effective

Too much and prolonged sitting may be a risk factors for cardiometabolic health. The UP4FUN intervention is a family-involved school-based intervention aiming at reducing and breaking up sitting time at home (with special emphasis on screen time), and breaking up sitting time in school among 10–12 year olds in different countries across Europe. In a paper just published in the journal Plos One -with Dr. Froydis Vik as first author- we report on the intervention's short term effects.
A total of 3147 pupils from Belgium, Germany, Greece, Hungary and Norway participated in a school-randomized controlled trial. The intervention included 1–2 school lessons per week for a period of six weeks, along with assignments for the children and their parents. Screen time and breaking up sitting time were registered by self-report and total sedentary time and breaking up sitting time by accelerometry. The effect of the intervention on these behaviors was analysed by multilevel regression analyses. All analyses were adjusted for baseline values and gender. No significant intervention effects were observed, neither for self-reported TV/DVD or computer/game console time, nor for accelerometer-assessed total sedentary time and number of breaks in sitting time. The intervention group did report more positive attitudes towards and preferences/liking for breaking up sitting time than the control group.
Overall, these results do not warrant wider dissemination of the present UP4FUN intervention.

What features do Dutch university students prefer in a smartphone application for promotion of physical activity?

The transition from adolescence to early adulthood is a critical period in which there is a decline in physical activity (PA). College and university students make up a large segment of this age group. Smartphones may be used to promote and support PA. The purpose of a qualitative study just published in International Journal of Behavioral Nutrition & Physical Activity, with Anouk Middelweerd as first author, was to explore Dutch students’ preferences regarding a PA application (PA app) for smartphones. Thirty Dutch students (aged 18–25 years) used a PA app for three weeks and subsequently attended focus group discussions. To streamline the discussion, a discussion guide was developed covering seven main topics, including general app usage, usage and appreciation of the PA app, appreciation of and preferences for its features and the sharing of PA accomplishments through social media. The discussions were audio and video recorded, transcribed and analysed according to conventional content analysis.
Participants preferred for PA apps a simple and structured layout without unnecessary features. Ideally, the PA app should enable users to tailor it to their personal preferences by including the ability to hide features. Participants preferred a companion website for detailed information about their accomplishments and progress, and they liked tracking their workout using GPS. They preferred PA apps that coached and motivated them and provided tailored feedback toward personally set goals. They appreciated PA apps that enabled competition with friends by ranking or earning rewards, but only if the reward system was transparent. They were not willing to share their regular PA accomplishments through social media unless they were exceptionally positive. In conclusion,  participants prefer PA apps that coach and motivate them, that provide tailored feedback toward personally set goals and that allow competition with friends.

Associations between active video gaming and other energy-balance related behaviours in adolescents

Active video games, i.e. video games that require physical activity for play, may contribute to reducing time spent in sedentary activities, increasing physical activity and preventing excessive weight gain in adolescents. Active video gaming can, however, only be beneficial for weight management when it replaces sedentary activities and not other physical activity, and when it is not associated with a higher energy intake. In a study just published in International Journal of Behavioral Nutrition and Physical Activity, we report an examination of the association between active video gaming and other energy-balance-related behaviours (EBRBs). Adolescents (12–16 years) with access to an active video game and who reported to spend at least one hour per week in active video gaming were invited to participate in the study. They were asked to complete electronic 24-hour recall diaries on five randomly assigned weekdays and two randomly assigned weekend-days in a one-month period, reporting on time spent playing active and non-active video games and on other EBRBs. Adolescents who reported playing active video games also reported spending more time playing non-active video games compared to adolescents who did not report playing active video games. No differences between these groups were found in other EBRBs. Among those who played active video games, active video game time was positively yet weakly associated with TV/DVD time and snack consumption. Active video game time was not significantly associated with other activities and sugar-sweetened beverages intake.
The results suggest that it is unlikely that time spent by adolescents in playing active video games replaces time spent in other physically active behaviours or sedentary activities. Spending more time playing active video games does seem to be associated with a small, but significant increase in intake of snacks. This suggests that interventions aimed at increasing time spent on active video gaming, may have unexpected side effects, thus warranting caution.